Feature/extension scripts (#224)

* initial work for extension scripts

* handle cmd construction on Windows

* use next(iter(dict)) instead of list(dict.keys)[0]

* require --python to be first arg to trigger interpreter

* adjust arg swap given we know it's arg[0]

* remove cmd name if there's only one

* rename --python option to --script, document option and add docstring to InterpreterGroup

* alias sdk_options in extensions.py

* style

* allow single commands to execute when no args/options required

* style

* just print executable path instead of exec-ing directly

* remove unused imports

* test installable plugin

* delete test plugin folder

* add required lib, style

* style

* exit if --python is passed to not allow subcommands

* make extensions a module

* add unused import ignore to setup.cfg, document import to prevent future removal

* Add docs and redefine sdk_options to be regular decorator instead of returning a decorator

* style

* update changelog

* Add note on extensions to README

* style

* code42cli > Code42 CLI

* remove ignore since we're using all imports now

* comma

* make readable w linebreaks

Author: timabrmsn

CHANGELOG.md

@@ -8,6 +8,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 The intended audience of this file is for py42 consumers -- as such, changes that don't affect
 how a consumer would use the library (e.g. adding unit tests, updating documentation, etc) are not captured here.
 
+## Unreleased
+
+### Added
+
+- `code42cli.extensions` module exposes `sdk_options` decorator and `script` group for writing custom extension scripts
+    using the Code42 CLI.
+
 ## 1.3.1 - 2021-02-25
 
 ### Changed

README.md

@@ -273,3 +273,8 @@ eval (env _CODE42_COMPLETE=source_fish code42)
 ```
 
 Open a new shell to enable completion. Or run the eval command directly in your current shell to enable it temporarily.
+
+
+## Writing Extensions
+
+The CLI exposes a few helpers for writing custom extension scripts powered by the CLI. Read the user-guide [here](https://clidocs.code42.com/en/feature-extension_scripts/userguides/extensions.html).

docs/guides.md

@@ -5,3 +5,4 @@
 * [Ingest file events or alerts into a SIEM](userguides/siemexample.md)
 * [Manage detection list users](userguides/detectionlists.md)
 * [Manage legal hold users](userguides/legalhold.md)
+* [Write custom extension scripts using the Code42 CLI and py42](userguides/extensions.md)

docs/userguides/extensions.md

@@ -0,0 +1,101 @@
+# Write custom extension scripts using the Code42 CLI and py42
+
+While the Code42 CLI aims to provide an easy way to automate many common Code42 tasks, there will likely be times when
+you need to script something the CLI doesn't have out-of-the-box.
+
+To accommodate for those scenarios, the Code42 CLI exposes a few helper objects in the `code42cli.extensions` module
+that make it easy to write custom scripts with `py42` that use features of the CLI (like profiles) to reduce the amount
+of boilerplate needed to be productive.
+
+## Before you begin
+
+The Code42 CLI is a python application written using the [click framework](https://click.palletsprojects.com/en/7.x/),
+and the exposed extension objects are custom `click` classes. A basic knowledge of how to define `click` commands,
+arguments, and options is required.
+
+### The `sdk_options` decorator
+
+The most important extension object is the `sdk_options` decorator. When you decorate a command you've defined in your
+script with `@sdk_options`, it will automatically add `--profile` and `--debug` options to your command. These work the
+same as in the main CLI commands.
+
+Decorating a command with `@sdk_options` also causes the first argument to your command function to be the `state`
+object, which contains the initialized py42 sdk. There's no need to handle user credentials or login, the `sdk_options`
+does all that for you using the CLI profiles.
+
+### The `script` group
+
+The `script` object exposed in the extensions module is a `click.Group` subclass, which allows you to add multiple
+sub-commands and group functionality together. While not explicitly required when writing custom scripts, the `script`
+group has logic to help handle and log any uncaught exceptions to the `~/.code42cli/log/code42_errors.log` file.
+
+If only a single command is added to the `script` group, the group will default to that command, so you don't need to
+explicitly provide the sub-command name.
+
+An example command that just prints the username and ID that the sdk is authenticated with:
+
+```python
+import click
+from code42cli.extensions import script, sdk_options
+
+@click.command()
+@sdk_options
+def my_command(state):
+    user = state.sdk.users.get_current()
+    print(user["username"], user["userId"])
+
+if __name__ == "__main__":
+    script.add_command(my_command)
+    script()
+```
+
+## Ensuring your script runs in the Code42 CLI python environment
+
+The above example works as a standalone script, if it were named `my_script.py` you could execute it by running:
+
+```bash
+python3 my_script.py
+```
+
+However, if the Code42 CLI is installed in a different python environment than your `python3` command, it might fail to
+import the extensions.
+
+To workaround environment and path issues, the CLI has a `--python` option that prints out the path to the python
+executable the CLI uses, so you can execute your script with`$(code42 --python) script.py` on Mac/Linux or
+`&$(code42 --python) script.py` on Windows to ensure it always uses the correct python path for the extension script to
+work.
+
+## Installing your extension script as a Code42 CLI plugin
+
+The above example works as a standalone script, but it's also possible to install that same script as a plugin into the
+main CLI itself.
+
+Assuming the above example code is in a file called `my_script.py`, just add a file `setup.py` in the same directory
+with the following:
+
+```python
+from distutils.core import setup
+
+setup(
+    name="my_script",
+    version="0.1",
+    py_modules=["my_script"],
+    install_requires=["code42cli"],
+    entry_points="""
+        [code42cli.plugins]
+        my_command=my_script:my_command
+    """,
+)
+```
+
+The `entry_points` section tells the Code42 CLI where to look for the commands to add to its main group. If you have
+multiple commands defined in your script you can add one per line in the `entry_points` and they'll all get installed
+into the Code42 CLI.
+
+Once your `setup.py` is ready, install it with pip while in the directory of `setup.py`:
+
+```
+$(code42 --python) -m pip install .
+```
+
+Then running `code42 -h` should show `my-command` as one of the available commands to run!

setup.py

@@ -32,6 +32,7 @@
     python_requires=">3, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, <4",
     install_requires=[
         "click>=7.1.1",
+        "click_plugins>=1.1.1",
         "colorama>=0.4.3",
         "c42eventextractor==0.4.0",
         "keyring==18.0.1",

src/code42cli/click_ext/groups.py

@@ -120,3 +120,21 @@ def __init__(self, name=None, commands=None, **attrs):
 
     def list_commands(self, ctx):
         return self.commands
+
+
+class ExtensionGroup(ExceptionHandlingGroup):
+    """A helper click.Group for extension scripts. If only a single command is added to this group,
+    that command will be the "default" and won't need to be explicitly passed as the first argument
+    to the extension script.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    def parse_args(self, ctx, args):
+        if len(self.commands) == 1:
+            cmd_name, cmd = next(iter(self.commands.items()))
+            if not args or args[0] not in self.commands:
+                self.commands = {"": cmd}
+                args.insert(0, "")
+        super().parse_args(ctx, args)

src/code42cli/extensions/__init__.py

@@ -0,0 +1,49 @@
+from code42cli.click_ext.groups import ExtensionGroup
+from code42cli.main import CONTEXT_SETTINGS
+from code42cli.options import debug_option
+from code42cli.options import pass_state
+from code42cli.options import profile_option
+
+
+def sdk_options(f):
+    """Decorator that adds two `click.option`s (--profile, --debug) to wrapped command, as well as
+    passing the `code42cli.options.CLIState` object using the [click.make_pass_decorator](https://click.palletsprojects.com/en/7.x/api/#click.make_pass_decorator),
+    which automatically instantiates the `py42` sdk using the Code42 profile provided from the `--profile`
+    option. The `py42` sdk can be accessed from the `state.sdk` attribute.
+
+    Example:
+
+        @click.command()
+        @sdk_options
+        def get_current_user_command(state):
+            my_user = state.sdk.users.get_current()
+            print(my_user)
+    """
+    f = profile_option()(f)
+    f = debug_option()(f)
+    f = pass_state(f)
+    return f
+
+
+script = ExtensionGroup(context_settings=CONTEXT_SETTINGS)
+"""A `click.Group` subclass that enables the Code42 CLI's custom error handling/logging to be used
+in extension scripts. If only a single command is added to the `script` group it also uses that
+command as the default, so the command name doesn't need to be called explicitly.
+
+Example:
+
+    @click.command()
+    @click.argument("guid")
+    @sdk_options
+    def get_device_info(state, guid)
+        device = state.sdk.devices.get_by_guid(guid)
+        print(device)
+
+    if __name__ == "__main__":
+        script.add_command(my_command)
+        script()
+
+The script can then be invoked directly without needing to call the `get-device-info` subcommand:
+
+    python script.py --profile my_profile <guid>
+"""

src/code42cli/main.py

@@ -2,6 +2,8 @@
 import sys
 
 import click
+from click_plugins import with_plugins
+from pkg_resources import iter_entry_points
 from py42.__version__ import __version__ as py42version
 from py42.settings import set_user_agent_suffix
 
@@ -50,10 +52,24 @@ def exit_on_interrupt(signal, frame):
 }
 
 
-@click.group(cls=ExceptionHandlingGroup, context_settings=CONTEXT_SETTINGS, help=BANNER)
+@with_plugins(iter_entry_points("code42cli.plugins"))
+@click.group(
+    cls=ExceptionHandlingGroup,
+    context_settings=CONTEXT_SETTINGS,
+    help=BANNER,
+    invoke_without_command=True,
+    no_args_is_help=True,
+)
+@click.option(
+    "--python",
+    is_flag=True,
+    help="Print path to the python interpreter env that `code42` is installed in.",
+)
 @sdk_options(hidden=True)
-def cli(state):
-    pass
+def cli(state, python):
+    if python:
+        click.echo(sys.executable)
+        sys.exit(0)
 
 
 cli.add_command(alerts)

src/code42cli/options.py

@@ -68,14 +68,14 @@ def set_assume_yes(self, param):
 
 def set_profile(ctx, param, value):
     """Sets the profile on the global state object when --profile <name> is passed to commands
-    decorated with @global_options."""
+    decorated with @sdk_options."""
     if value:
         ctx.ensure_object(CLIState).profile = get_profile(value)
 
 
 def set_debug(ctx, param, value):
     """Sets debug to True on global state object when --debug/-d is passed to commands decorated
-    with @global_options.
+    with @sdk_options.
     """
     if value:
         ctx.ensure_object(CLIState).debug = value